OPTICAL LAMINATE FOR FRONT SURFACE OF IN-CELL TOUCH PANEL LIQUID CRYSTAL ELEMENT AND IN-CELL TOUCH PANEL LIQUID CRYSTAL DISPLAY DEVICE USING SAME

• US 20150301385A1
• Filed: 10/25/2013
• Published: 10/22/2015
• Est. Priority Date: 10/29/2012
• Status: Active Grant

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Tsunekawa, Masayuki
• Granted Patent: US 9,880,419 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B32B 2457/202 LCD, i.e. liquid crystal displays
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02B 5/3041 comprising multiple thin layers, e.g. multilayer stacks
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 2201/50 Protective arrangements

Abstract

Provided is an optical laminate for a front surface of an in-cell touch panel liquid crystal element in which the thickness can be reduced while necessary functions are ensured, and a liquid crystal screen becoming cloudy can be prevented.

The optical laminate for a front surface of an in-cell touch panel liquid crystal element comprises a phase difference plate, a polarizing film, and a surface protective film in this order, and further comprises a conductive layer. The surface protective film has optical anisotropy that scatters linear polarized light emitted from the polarizing film, and a thickness of the optical laminate is in a range of 90 μm to 450 μm.

Claims

1. An optical laminate for a front surface of an in-cell touch panel liquid crystal element comprising:

a phase difference plate;

a polarizing film;

a surface protective film in this order; and

a conductive layer,

wherein the surface protective film has optical anisotropy that scatters linear polarized light emitted from the polarizing film, and a thickness of the optical laminate is in a range of 90 μ

m to 450 μ

m.

2. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the surface protective film comprises a cured layer on the substrate having optical anisotropy that scatters linear polarized light emitted from the polarizing film.

3. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 2,

wherein the substrate having optical anisotropy is a plastic film having a retardation value in a range of 3000 nm to 30000 nm or a plastic film having a ¼

wavelength phase difference.

4. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 2,

wherein the substrate having optical anisotropy is obtained by attaching a plastic film having a ¼

wavelength phase difference and an optical isotropic film.

5. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 4,

wherein the plastic film having a ¼

wavelength phase difference is a biaxially stretched polyester film having a thickness in a range of 4 μ

m to 15 μ

m.

6. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 2,

wherein the optical laminate comprises the cured layers on both surfaces of the substrate having optical anisotropy.

7. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 2,

wherein the cured layer is formed of an ionizing radiation curable resin composition.

8. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein a surface resistivity of the conductive layer is in a range of 1.0×

10⁸Ω

/□

to 2.0×

10⁹Ω

/□

.

9. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the conductive layer has a bilayer structure of a first conductive layer and a second conductive layer.

10. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 9,

wherein the first conductive layer comprises fine metal particles or fine metal oxide particles, and the second conductive layer comprises fine conductive particles.

11. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the optical laminate comprises the conductive layer on a surface of the phase difference plate opposite to the polarizing film.

12. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein an earthing treatment is carried out starting from a surface of the conductive layer.

13. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the polarizing film is a stretched polyvinyl alcohol film.

14. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the phase difference plate comprises a layer comprising a refractive index anisotropic material on a resin film.

15. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the phase difference plate, the polarizing film, the surface protective film, and the conductive layer are attached together without using an adhesion layer.

16. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 2,

wherein the substrate having optical anisotropy comprises an ultraviolet absorbing agent.

17. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein a thickness of the phase difference plate is in a range of 25 μ

m to 60 μ

m, a thickness of the polarizing film is in a range of 2 μ

m to 30 μ

m, a thickness of the surface protective film is in a range of 60 μ

m to 350 μ

m, and a thickness of the conductive layer is in a range of 0.1 μ

m to 10 μ

m.

18. The optical laminate for a front surface of an in-cell touch panel liquid crystal element according to claim 1,

wherein the in-cell touch panel liquid crystal element is an electrostatic capacity-type in-cell touch panel liquid crystal element.

19. An in-cell touch panel liquid crystal display device comprising:

an in-cell touch panel liquid crystal element; and

the optical laminate according to claim 1,

wherein a surface of the optical laminate, which is present on the opposite side to the surface protective film on the basis of the polarizing film, attaching onto the in-cell touch panel liquid crystal element.

20. The in-cell touch panel liquid crystal display device according to claim 19,

wherein an earthing treatment is carried out starting from a surface of the conductive layer in the optical laminate.